In the event that positive outcomes are verified, there is a compelling case for extending the experiment across the Indian Ocean islands
An experiment to test dried palm leaves barriers against soil erosion in Praslin, Seychelles, yields positive results
March 7, 2023
From September to December 2022, the UNDP Mauritius and Seychelles Accelerator Lab partnered with Terrestrial Restoration Action Society Seychelles (TRASS) and the Seychelles Parks and Gardens Authority (SPGA), to test whether dried palm leaves barriers could help to curb the effects of soil erosion in Seychelles. From the results collected during rain showers in December, the experience turned out to be positive.
The experimental results
The steep slopes of Praslin Island in Seychelles are susceptible to soil erosion, particularly during the rainy summer months. To find a nature-based solution to this problem, the UNDP Accelerator Lab enlisted the expertise of Dr. Victorin Laboudallon and Dr. Elvina Henriette from TRASS. They sought to determine whether barriers made from dried palm leaves, which are readily available on the island, could effectively mitigate soil erosion. Allen Cedras, CEO of the Seychelles Parks and Gardens Authority (SPGA), supported the initiative by identifying plots of land at Pasquière and Pointe Chevalier for the experiment.
Over the course of September to November, the TRASS team established multiple microplots to conduct the experiment, and compared soil loss on the identified slopes with and without dried palm leaf barriers, which served as the control group. In addition, the team tested the efficacy of barriers made from bamboo or cocoplum to assess the effectiveness of different materials.
Despite below-average rainfall in December 2022, a sufficient number of samples were collected to make statistically significant observations. The obtained results demonstrate that all materials utilized for constructing the barriers were effective in providing protection against soil erosion. Specifically, the implementation of barriers composed of dried palm leaves on gentle slopes led to a reduction in soil erosion by 9 to 16 times, whereas the utilization of bamboo or cocoplum barriers resulted in a reduction of soil loss by approximately 10 times. On steep slopes, dried palm leaf barriers proved even more efficient, reducing soil erosion by 15 to 20 during the experiment.
Although the initial experiment has concluded, ongoing monitoring of the requested plots of land on Praslin is being conducted by TRASS, with further results expected after the rainy season, spanning from January to March. In the event that positive outcomes are verified, there is a compelling case for extending the experiment across the Indian Ocean islands, which share many commonalities regarding soil erosion. Such an initiative would offer opportunities for fruitful South-South exchanges in the realm of conservation. Drs. Victorin Laboudallon and Elvina Henriette could establish links with their counterparts in Mauritius and Rodrigues, and with the support of UNDP, they could identify pragmatic solutions for the challenges arising from climate change.
It is worth noting that the UNDP Acc Lab team, in collaboration with TRASS and SPGA, successfully executed this experiment without any in-person meetings. Instead, all coordination and discussion tasks were conducted virtually through Zoom. While not optimal, the project's success was made possible through the kindness and enthusiasm of all parties involved.
This blog was written with the contributions of Ms Vicky Athanase, Project Manager, (TRASS); Ms Jeanna Stravens, Research and Monitoring Officer, (TRASS); Mr Allen Cedras, Chief Executive Officer at the Seychelles Parks and Gardens Authority (SPGA) and Bernadette Dogley, ex-National UN Community Volunteer, UNDP Mauritius and Seychelles Accelerator Lab.
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